Love took Edith Windsor to the marriage altar. A big tax bill after the death of her first spouse took her to the Supreme Court, which struck down critical parts of a U.S. marriage law in a ruling that made Windsor a gay rights hero and paved a path toward legalizing same-sex nuptials nationwide.

Windsor, who marveled at the arc of gay rights in her lifetime, died Tuesday in New York at age 88, said her lawyer, Roberta Kaplan. The cause of her death wasn't given, but she had struggled with heart issues.

"I grew up knowing that society thought I was inferior," she said in 2012. "Did I ever think we would be discussing equality in marriage? Never. It was just so far away."

Windsor was 81 when she brought a lawsuit that proved to be a turning point for gay rights. The impetus was the 2009 death of her spouse, Thea Spyer, a psychologist.

The women had married legally in Canada in 2007 after spending more than 40 years together, but under the U.S. Defense of Marriage Act she was barred from getting the usual exemption from federal taxes on Spyer's estate. That meant Windsor faced a $360,000 tax bill that heterosexual couples would not have.

Outraged, she went to court, knowing that the case was about more than taxes or even marriage.

"It's a very important case. It's bigger than marriage, and I think marriage is major. I think if we win, the effect will be the beginning of the end of stigma," she said in 2012 after the Supreme Court agreed to hear the case.

Win she did: The justices ruled 5-4 in June 2013 that a provision in the law barring the U.S. government from recognizing same-sex unions was unconstitutional.

The opinion didn't legalize same-sex marriage, but it marked a key moment of encouragement for gay marriage supporters then confronting a nationwide patchwork of laws that outlawed such unions in roughly three dozen states.

It also affronted conservatives who hewed to defining marriage as between a man and a woman. Then-Supreme Court Justice Antonin Scalia predicted the ruling would be used to upend state restrictions on marriage and warned: "The only thing that will 'confine' the court's holding is its sense of what it can get away with."

Ultimately, the opinion in Windsor's case became the basis for a wave of federal court rulings that struck down state marriage bans and led to a 2015 Supreme Court ruling giving same-sex couples the right to marry from coast to coast.

Former President Barack Obama called Windsor one of the "quiet heroes" whose persistence had furthered the cause of equality.

"Few were as small in stature as Edie Windsor — and few made as big a difference to America," the Democrat said in a statement Tuesday, adding that he had spoken to her a few days earlier.

Spyer came into her life in 1963, and they became a couple two years later. In court documents, Windsor said she told Spyer, "'If it still feels this goofy joyous, I'd like us to spend the rest of our lives together.' And we did."

Concerned that an engagement ring would bring unwanted attention to Windsor's sexual orientation, Spyer gave her a diamond brooch instead. It was, Windsor later said in court documents, "just one of many ways in which Thea and I had to mold our lives to make our relationship invisible."

Spyer was diagnosed with multiple sclerosis in 1977. The women married in Canada when they realized they might not live long enough to see New York legalize same-sex marriage. It did in 2011.